I will have to ask my friend that is building a new house. He has installed what is supposed to be the quietest unit on the market and one of the most effecient. For $22,000 it better be; it is a 2 zone setup and they assured him he wont hear it running. It was just installed a couple of weeks ago after the house was in the dry so it may be a month or so before we can really find out just how good it is. Later Bill